Commit 6f5fd837 authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by Michael S. Tsirkin
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libvhost-user: support many virtqueues 



Currently libvhost-user is hardcoded to at most 8 virtqueues.  The
device backend should decide the number of virtqueues, not
libvhost-user.  This is important for multiqueue device backends where
the guest driver needs an accurate number of virtqueues.

This change breaks libvhost-user and libvhost-user-glib API stability.
There is no stability guarantee yet, so make this change now and update
all in-tree library users.

This patch touches up vhost-user-blk, vhost-user-gpu, vhost-user-input,
vhost-user-scsi, and vhost-user-bridge.  If the device has a fixed
number of queues that exact number is used.  Otherwise the previous
default of 8 virtqueues is used.

vu_init() and vug_init() can now fail if malloc() returns NULL.  I
considered aborting with an error in libvhost-user but it should be safe
to instantiate new vhost-user instances at runtime without risk of
terminating the process.  Therefore callers need to handle the vu_init()
failure now.

vhost-user-blk and vhost-user-scsi duplicate virtqueue index checks that
are already performed by libvhost-user.  This code would need to be
modified to use max_queues but remove it completely instead since it's
redundant.

Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarMarc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20190626074815.19994-3-stefanha@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent db68f4ff

contrib/libvhost-user/libvhost-user-glib.c

+9 −3
Original line number Diff line number Diff line
@@ -131,18 +131,24 @@ static void vug_watch(VuDev *dev, int condition, void *data) 
    }

}



void

vug_init(VugDev *dev, int socket,

bool

vug_init(VugDev *dev, uint16_t max_queues, int socket,

         vu_panic_cb panic, const VuDevIface *iface)

{

    g_assert(dev);

    g_assert(iface);



    vu_init(&dev->parent, socket, panic, set_watch, remove_watch, iface);

    if (!vu_init(&dev->parent, max_queues, socket, panic, set_watch,

                 remove_watch, iface)) {

        return false;

    }



    dev->fdmap = g_hash_table_new_full(NULL, NULL, NULL,

                                       (GDestroyNotify) g_source_destroy);



    dev->src = vug_source_new(dev, socket, G_IO_IN, vug_watch, NULL);



    return true;

}



void

contrib/libvhost-user/libvhost-user-glib.h

+1 −1
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ typedef struct VugDev { 
    GSource *src;

} VugDev;



void vug_init(VugDev *dev, int socket,

bool vug_init(VugDev *dev, uint16_t max_queues, int socket,

              vu_panic_cb panic, const VuDevIface *iface);

void vug_deinit(VugDev *dev);

contrib/libvhost-user/libvhost-user.c

+24 −9
Original line number Diff line number Diff line
@@ -493,9 +493,9 @@ vu_get_features_exec(VuDev *dev, VhostUserMsg *vmsg) 
static void

vu_set_enable_all_rings(VuDev *dev, bool enabled)

{

    int i;

    uint16_t i;



    for (i = 0; i < VHOST_MAX_NR_VIRTQUEUE; i++) {

    for (i = 0; i < dev->max_queues; i++) {

        dev->vq[i].enable = enabled;

    }

}
@@ -916,7 +916,7 @@ vu_check_queue_msg_file(VuDev *dev, VhostUserMsg *vmsg) 
{

    int index = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;



    if (index >= VHOST_MAX_NR_VIRTQUEUE) {

    if (index >= dev->max_queues) {

        vmsg_close_fds(vmsg);

        vu_panic(dev, "Invalid queue index: %u", index);

        return false;
@@ -1213,7 +1213,7 @@ vu_set_vring_enable_exec(VuDev *dev, VhostUserMsg *vmsg) 
    DPRINT("State.index: %d\n", index);

    DPRINT("State.enable:   %d\n", enable);



    if (index >= VHOST_MAX_NR_VIRTQUEUE) {

    if (index >= dev->max_queues) {

        vu_panic(dev, "Invalid vring_enable index: %u", index);

        return false;

    }
@@ -1582,7 +1582,7 @@ vu_deinit(VuDev *dev) 
    }

    dev->nregions = 0;



    for (i = 0; i < VHOST_MAX_NR_VIRTQUEUE; i++) {

    for (i = 0; i < dev->max_queues; i++) {

        VuVirtq *vq = &dev->vq[i];



        if (vq->call_fd != -1) {
@@ -1627,18 +1627,23 @@ vu_deinit(VuDev *dev) 
    if (dev->sock != -1) {

        close(dev->sock);

    }



    free(dev->vq);

    dev->vq = NULL;

}



void

bool

vu_init(VuDev *dev,

        uint16_t max_queues,

        int socket,

        vu_panic_cb panic,

        vu_set_watch_cb set_watch,

        vu_remove_watch_cb remove_watch,

        const VuDevIface *iface)

{

    int i;

    uint16_t i;



    assert(max_queues > 0);

    assert(socket >= 0);

    assert(set_watch);

    assert(remove_watch);
@@ -1654,18 +1659,28 @@ vu_init(VuDev *dev, 
    dev->iface = iface;

    dev->log_call_fd = -1;

    dev->slave_fd = -1;

    for (i = 0; i < VHOST_MAX_NR_VIRTQUEUE; i++) {

    dev->max_queues = max_queues;



    dev->vq = malloc(max_queues * sizeof(dev->vq[0]));

    if (!dev->vq) {

        DPRINT("%s: failed to malloc virtqueues\n", __func__);

        return false;

    }



    for (i = 0; i < max_queues; i++) {

        dev->vq[i] = (VuVirtq) {

            .call_fd = -1, .kick_fd = -1, .err_fd = -1,

            .notification = true,

        };

    }



    return true;

}



VuVirtq *

vu_get_queue(VuDev *dev, int qidx)

{

    assert(qidx < VHOST_MAX_NR_VIRTQUEUE);

    assert(qidx < dev->max_queues);

    return &dev->vq[qidx];

}

contrib/libvhost-user/libvhost-user.h

+7 −3
Original line number Diff line number Diff line
@@ -25,7 +25,6 @@ 
#define VHOST_USER_F_PROTOCOL_FEATURES 30

#define VHOST_LOG_PAGE 4096



#define VHOST_MAX_NR_VIRTQUEUE 8

#define VIRTQUEUE_MAX_SIZE 1024



#define VHOST_MEMORY_MAX_NREGIONS 8
@@ -353,7 +352,7 @@ struct VuDev { 
    int sock;

    uint32_t nregions;

    VuDevRegion regions[VHOST_MEMORY_MAX_NREGIONS];

    VuVirtq vq[VHOST_MAX_NR_VIRTQUEUE];

    VuVirtq *vq;

    VuDevInflightInfo inflight_info;

    int log_call_fd;

    int slave_fd;
@@ -362,6 +361,7 @@ struct VuDev { 
    uint64_t features;

    uint64_t protocol_features;

    bool broken;

    uint16_t max_queues;



    /* @set_watch: add or update the given fd to the watch set,

     * call cb when condition is met */
@@ -391,6 +391,7 @@ typedef struct VuVirtqElement { 
/**

 * vu_init:

 * @dev: a VuDev context

 * @max_queues: maximum number of virtqueues

 * @socket: the socket connected to vhost-user master

 * @panic: a panic callback

 * @set_watch: a set_watch callback
@@ -398,8 +399,11 @@ typedef struct VuVirtqElement { 
 * @iface: a VuDevIface structure with vhost-user device callbacks

 *

 * Intializes a VuDev vhost-user context.

 *

 * Returns: true on success, false on failure.

 **/

void vu_init(VuDev *dev,

bool vu_init(VuDev *dev,

             uint16_t max_queues,

             int socket,

             vu_panic_cb panic,

             vu_set_watch_cb set_watch,

contrib/vhost-user-blk/vhost-user-blk.c

+9 −7
Original line number Diff line number Diff line
@@ -25,6 +25,10 @@ 
#include <sys/ioctl.h>

#endif



enum {

    VHOST_USER_BLK_MAX_QUEUES = 8,

};



struct virtio_blk_inhdr {

    unsigned char status;

};
@@ -334,12 +338,6 @@ static void vub_process_vq(VuDev *vu_dev, int idx) 
    VuVirtq *vq;

    int ret;



    if ((idx < 0) || (idx >= VHOST_MAX_NR_VIRTQUEUE)) {

        fprintf(stderr, "VQ Index out of range: %d\n", idx);

        vub_panic_cb(vu_dev, NULL);

        return;

    }



    gdev = container_of(vu_dev, VugDev, parent);

    vdev_blk = container_of(gdev, VubDev, parent);

    assert(vdev_blk);
@@ -631,7 +629,11 @@ int main(int argc, char **argv) 
        vdev_blk->enable_ro = true;

    }



    vug_init(&vdev_blk->parent, csock, vub_panic_cb, &vub_iface);

    if (!vug_init(&vdev_blk->parent, VHOST_USER_BLK_MAX_QUEUES, csock,

                  vub_panic_cb, &vub_iface)) {

        fprintf(stderr, "Failed to initialized libvhost-user-glib\n");

        goto err;

    }



    g_main_loop_run(vdev_blk->loop);